redletterdave writes: "For the second time in a row, Microsoft's Security Essentials failed to earn certification from AV-Test, the independent German testing lab best known for evaluating the effectiveness of antivirus software. Out of 25 different security programs tested by AV-Test, including software from McAfee, Norman, Kaspersky, and others, Microsoft’s Security Essentials was just one out of three that failed to gain certification. These results are noteworthy because Microsoft Security Essentials is currently (as of December) the most popular security suite in North America and the world."